Which of the following would be considered a nonparametric test?

I. A test to determine if two events are truly independent of each other.
II. A test to determine if the variances of two populations are equal.
III. A test to determine if the means of two populations are equal.
IV. A test dealing with a data set that's made up of rankings, as opposed to nominal values.

Explanation: Any test that deals with the mean or the variance of the population is regarded to be a "parametric" test. Consequently, all other tests would be regarded as "nonparametric" tests.